Crystals have been grown of the V-1-ATPase sector of the V-type ATP synthase complex (V0V1) from the thermophilic eubacterium Thermus thermophilus HB8. These crystals are grown by the vapor diffusion method in the presence of 5 mM Mg-ADP, from solutions containing 100 mM sodium acetate and 2 M sodium formate, pH 5.5. The crystals diffracted X rays beyond 3.4 Angstrom in resolution on a synchrotron radiation source. The crystals belong to the trigonal space group P3, with unit cell dimensions of a = b = 89.0 Angstrom, c = 179.2 Angstrom, and gamma = 120 degrees The unit cell presumably contains one molecule of V-1-ATPase and the V-m value is calculated as 3.0 Angstrom (3)/Da.